﻿using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Windows.Forms;

namespace Thinksea.Windows.Forms
{
    /// <summary>
    /// 用于实现不规则图像控件的功能类。.
    /// </summary>
    public class AnomalisticControl
    {
        /// <summary>
        /// 一个构造方法。
        /// </summary>
        public AnomalisticControl()
        { }

        /// <summary>
        /// 绘制不规则图像控件。
        /// </summary>
        /// <param name="control">承载图像的控件。</param>
        /// <param name="bitmap">要绘制的图像。</param>
        /// <remarks>
        /// The Control object to apply the region to
        /// The Bitmap object to create the region from
        /// </remarks>
        public static void CreateControlRegion(Control control, Bitmap bitmap)
        {
            CreateControlRegion(control, bitmap, true);
        }

        /// <summary>
        /// 绘制不规则图像控件。
        /// </summary>
        /// <param name="control">承载图像的控件。</param>
        /// <param name="bitmap">要绘制的图像。</param>
        /// <param name="AutoSize">是否调整控件的尺寸使其符合显示图像。</param>
        /// <remarks>
        /// The Control object to apply the region to
        /// The Bitmap object to create the region from
        /// </remarks>
        public static void CreateControlRegion(Control control, Bitmap bitmap, bool AutoSize)
        {
            // Return if control and bitmap are null
            if (control == null || bitmap == null)
                return;

            // Set our control's size to be the same as the bitmap
            if (AutoSize)
            {
                control.Width = bitmap.Width;
                control.Height = bitmap.Height;
            }

            // Check if we are dealing with Form here
            if (control is System.Windows.Forms.Form)
            {
                // Cast to a Form object
                Form form = (Form)control;

                // Set our form's size to be a little larger that the bitmap just 
                // in case the form's border style is not set to none in the first place
                if (AutoSize)
                {
                    form.Width += 15;
                    form.Height += 35;
                }

                // No border
                form.FormBorderStyle = FormBorderStyle.None;

                // Set bitmap as the background image
                form.BackgroundImage = bitmap;

                // Calculate the graphics path based on the bitmap supplied
                GraphicsPath graphicsPath = CalculateControlGraphicsPath(bitmap);

                // Apply new region
                form.Region = new Region(graphicsPath);
            }
            // Check if we are dealing with Button here
            else// if (control is System.Windows.Forms.Button)
            {
                // Cast to a button object
                //Button button = (Button)control;

                // Do not show button text
                //control.Text = "";

                // Change cursor to hand when over button
                //control.Cursor = Cursors.Hand;

                // Set background image of button
                control.BackgroundImage = bitmap;

                // Calculate the graphics path based on the bitmap supplied
                GraphicsPath graphicsPath = CalculateControlGraphicsPath(bitmap);

                // Apply new region
                control.Region = new Region(graphicsPath);
            }

        }

        /// <summary>
        /// Calculate the graphics path that representing the figure in the bitmap 
        /// excluding the transparent color which is the top left pixel.
        /// </summary>
        /// <returns>计算控件图像路径。</returns>
        /// <remarks>
        /// The Bitmap object to calculate our graphics path from
        /// </remarks>
        private static GraphicsPath CalculateControlGraphicsPath(Bitmap bitmap)
        {
            // Create GraphicsPath for our bitmap calculation
            GraphicsPath graphicsPath = new GraphicsPath();

            // Use the top left pixel as our transparent color
            Color colorTransparent = bitmap.GetPixel(0, 0);

            // This is to store the column value where an opaque pixel is first found.
            // This value will determine where we start scanning for trailing opaque pixels.
            int colOpaquePixel = 0;

            // Go through all rows (Y axis)
            for (int row = 0; row < bitmap.Height; row++)
            {
                // Reset value
                colOpaquePixel = 0;

                // Go through all columns (X axis)
                for (int col = 0; col < bitmap.Width; col++)
                {
                    // If this is an opaque pixel, mark it and search for anymore trailing behind
                    if (bitmap.GetPixel(col, row) != colorTransparent)
                    {
                        // Opaque pixel found, mark current position
                        colOpaquePixel = col;

                        // Create another variable to set the current pixel position
                        int colNext = col;

                        // Starting from current found opaque pixel, search for anymore opaque pixels 
                        // trailing behind, until a transparent pixel is found or minimum width is reached
                        for (colNext = colOpaquePixel; colNext < bitmap.Width; colNext++)
                            if (bitmap.GetPixel(colNext, row) == colorTransparent)
                                break;

                        // Form a rectangle for line of opaque pixels found and add it to our graphics path
                        graphicsPath.AddRectangle(new Rectangle(colOpaquePixel, row, colNext - colOpaquePixel, 1));

                        // No need to scan the line of opaque pixels just found
                        col = colNext;
                    }
                }
            }

            // Return calculated graphics path
            return graphicsPath;
        }
    }

}
